CHANGING OF THE GARDEN: This weekend may seem a little early for folks in the snowverwhelmed Northeast to start thinking about their spring vegetable gardens, but the Green Fork reports that a couple of high-profile rooftop growers in Brooklyn — Annie Novak and Ben Flanner (pictured), two of MNN's "40 farmers under 40" in 2009 — are already hard at work on theirs. Novak has begun sowing seeds indoors while she waits for the rooftop soil to thaw, and on top of expanding the farm itself in its second year, she's working on adding the nation's first roof-based community-supported agriculture program, allowing customers to buy shares of the farm's produce in advance. Meanwhile, Flanner is partnering with a fellow rooftop-farm startup called Brooklyn Grange, and the two plan to reopen their popular open market in May. Outside the Northeast, winter's final frost is getting near for many anxious agrarians, meaning time is running short to plan and pick out seeds, prune trees and shrubs, and start planting certain crops in greenhouses. The Montgomery Advertiser and the Mobile Press-Register offer some tips for getting started in warmer climates, while the Detroit News' Jeff Ball highlights "yardsharing," a method of collaborative farming that can help inexperienced green thumbs join in the growing trend of home gardening. (Sources: Green Fork, Montgomery Advertiser, Mobile Press-Register, Detroit News)

BREAKING THE ICE: A 60-mile-long iceberg has smashed into Antarctica, breaking off a new chunk of ice three times the size of [skipwords]New York[/skipwords] City, scientists announced Friday, warning that the collision could have drastic consequences for the planet's sea life. The new iceberg was dislodged from Mertz Glacier, one of the few places on Earth where cold, dense water sinks all the way down to ocean basins, where it feeds global ocean currents with oxygen. Now that this 982-square-mile piece of the glacier is missing, sea ice will likely fill its place, hindering that cold, dense water's ability to sink — and potentially robbing the oceans of a major oxygen source. "There may be regions of the world's oceans that lose oxygen, and then of course most of the life there will die," a German chemical oceanographer tells the AP. Earlier this month, the U.S. Geological Survey announced that every ice front on the southern peninsula of Antarctica has been retreating over the last 63 years, with the most severe melting occurring since 1990. (Sources: Associated Press, Sydney Morning Herald, BBC News)

WHALE WARS: SeaWorld Orlando will keep the killer whale that killed its trainer on Wednesday, arguing that calls to release or euthanize the animal are misguided. A 30-year-old male orca named Tilikum drowned 40-year-old trainer Dawn Brancheau (pictured together at right in 2005) by grabbing her ponytail and thrashing her around underwater, all in front of a horrified audience at the Florida theme park. It was the third human death linked to Tilikum in the past two decades, but SeaWorld officials point out that he has been in captivity too long now to survive in the wild, and that killing him isn't an option since he's such an important part of the park's breeding program. SeaWorld has suspended all orca shows at its three parks in Orlando, San Antonio and San Diego while it reviews procedures, and officials say they'll tighten the already-strict rules for dealing with Tilikum. (Sources: MSNBC, AP)

WRITING ON THE WAL: Mega-retailer Wal-Mart promised on Thursday that it will slash 20 million metric tons of greenhouse gas emissions from its sprawling supply chain by 2015, a move that would be equivalent to removing nearly 4 million cars from the road for a year. Wal-Mart says the reductions will more than make up for the expected growth of its carbon footprint over the next five years, pointing out that they'll span the supply chain from manufacturing to transportation to the sales floor. The company will focus on four of its most carbon-intensive product categories — bread, clothing, meat and milk — and push its suppliers to reinvent how these goods are sourced, made, packaged and moved. "We need to continue to build stores and add retail selling space," says Wal-Mart CEO and President Mike Duke. "Yet we know we need to get ready for a world in which energy will only be more expensive and there will only be a greater need to operate with less carbon in the supply chain." (Sources: Washington Post, New York Times, AP)

GREEN GOLD: As the Vancouver Winter Olympics wind down this weekend, the Los Angeles Times takes a look at the Canadian city's quest to be the greenest Olympics yet, as well as the early indications of how it's doing. Mayor Gregor Robertson (pictured) was a driving force behind the Games' eco-efforts, as the former organic farmer and juice-company executive pressed for a variety of energy-saving measures, and even eschewed his official Olympic chauffeur, instead showing up at events on his battered mountain bike. From medals made with e-waste to a LEED-certified athlete's village, the Vancouver Olympics have repeatedly earned praise for their green sheen, even though officials cut down thousands of trees to make room for a new highway and cross-country skiing trails, and had to truck in snow due to warm weather. Energy savings over the first five days totaled 112,700 kilowatt hours, the Times reports, and sponsors have voluntarily offset about 75 percent of their share in the Olympics' carbon emissions. (Source: Los Angeles Times)

SMOUND EFFECTS: If you've ever thought hot dogs smelled better with the sound of a crowded stadium roaring in the background, you were probably right, according to a new study published in the Journal of Neuroscience. You can thank your sense of "smound" for that, the name researchers have given to a hybrid sense of smell and sound, which they say seems to link the way food smells and the sounds we hear while eating it. A researcher at New York's Nathan S. Kline Institute for Psychiatric Research first discovered smound while observing brain scans of lab mice — when he put down his coffee mug, he noticed that the clunk of it hitting his desk produced a flurry of activity in the part of the mice's brains that handles odor detection. When he repeated the accidental experiment, he realized that sound and smell are apparently intertwined in the brain, with mice's brain cells firing more feverishly when presented with both in combination. "While we like to think that there are five separate senses, that's not the way it works," another neurobiologist tells Scientific American. "What your brain really does is take objects and process them." (Sources: Discoblog, Scientific American)

Russell McLendon

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Photo (Annie Novak and Ben Flanner): Novak/Flanner

Photo (dislodged iceberg in Antarctica): Commonwealth of Australia/AP

Photo (trainer Dawn Brancheau with Tilikum on Sept. 4, 2005): ZUMA Press

Photo (Wal-Mart in Weymouth, Mass.): Michael Dwyer/AP

Photo (Vancouver Mayor Gregor Roberton): Jeff Vinnick/Getty Images

Photo (lab rat): U.S. Energy Department

Russell McLendon ( @russmclendon ) writes about humans and other wildlife.